1. Field of the Invention
The present invention relates to door lock hardware, and in particular to snap-in request-to-exit switches that can be installed in electrified lock sets and other door latch mechanisms in the field.
2. Description of the Prior Art
Some security doors are normally kept locked and a card access or keypad system is required to gain entry. An electromechanical device in the door is energized at the presentation of a valid card, key fob, or entry code, and the door lock is temporarily released. During this time, the electromechanical device can be heard to buzz or click and most people know that such security doors can then be pushed or pulled open.
Sometimes the alarm system will have to be signaled to call attention to the fact a user wants to go through a locked security door from the inside out, or in an egress situation. So, request-to-exit switches have been installed in special models by the lock manufacturers. These can sense when a user turns a door knob wanting to egress, thereby shunting, or stopping an alarm from sounding, since there is no perceived threat to the system integrity for an authorized, or requested exit.
Special orders are required for these models of door locks, and the costs are significant. Installers must either order a supply of specially equipped locks, or return the originals for retrofitting, or install difficult and complex field switches which require lock disassembly and/or modification. Either way can be expensive and time consuming.
So what is needed is an easy-to-install switch that can be added in later to only those electrified locks that actually require a request-to-exit function. The switch should be simple and easy to install correctly, and it should function properly without needing adjustments. An economic construction should be used so that keeping inventories of a variety of switches for a variety of matching electrified locks is practical and affordable by the average installer.